Hyparrhenia hirta (L.) Stapf

Introduction

Hyparrhenia hirta is recognized by its hard basal tussock, rough narrow leaves and a scanty panicle of pairs of white villous racemes which do not deflex (bend downwards).

Description

Description

Hyparrhenia hirta is a wiry tufted perennial grass usually 300-800 mm high, rhizomatous and with slender culms. The leaf blade is 20-150 x 1-2(-4) mm. The panicle is scanty, consisting of 2-10 raceme pairs which are 20-40 mm long, never deflexed, bases unequal, cylindrical, 8-14 awns, 10-35 mm long, with hairs up to 0.3 mm long. The base of the upper raceme has 0-1 homogamous (same sex) pairs of spikelets. A sessile spikelet is 4.0-6.5 mm long, yellowish green to violet, white-villous and the callus is acute. The pedicelled spikelet is white villous and awnless. Flowering time: September to June. See glossary for terms in Gibbs Russell et al. (1990).

Conservation Status

Status

The SANBI Threatened Plants Programme has not, as yet, indicated its conservation status, but so far, Hyparrhenia hirta is widespread, and is good for grazing in spring and early summer, so conservation is practised indirectly.

Distribution and habitat

Distribution description

Hyparrhenia hirta is common in southern Africa and occurs throughout Africa to the Mediterranean region and Pakistan. It has also been introduced to other parts of the world. It occurs in open grassland, on rocky slopes and along rivers on most soil types, with a preference for well-drained, lighter textured granites to heavy black, stony soils.

It forms dense stands in disturbed areas such as uncultivated lands and roadsides where it can keep out other grasses for many years. The species occupies the largest area of road verges along the entire urban to rural gradient of southern Africa.

Derivation of name and historical aspects

History

Hyparrhenia is derived from the Greek words hypo, meaning under, and arren, meaning masculine, alluding to the male spikelets at the bases of the racemes. The species name hirta is from the Latin word meaning hairy, probably referring to the hairy spikelets.

The genus Hyparrhenia has ± 55 species, mostly in Africa, a few species in other tropical regions and the Mediterranean, and 20 in southern Africa, where it is widespread.

Ecology

Ecology

Pollination and seed dispersal of Hyparrhenia hirta are by wind.

Hyparrhenia hirta is the most competitive species in infertile areas, but not in areas where other fertile species occur. Once established, Hyparrhenia hirta is difficult to control.

Uses

Use

Hyparrhenia hirta is probably the most popular thatching grass used in South Africa. It is grazed by livestock early in the growing season and after fires, but becomes less palatable for grazing later. In South Africa and the USA this grass is seen as a drought resistant grass, which protects the soil and stabilizes hard, gravelly soil and eroded places. It is also used to weave mats and baskets.

Growing Hyparrhenia hirta

Grow

Hyparrhenia hirta is self-fertile, enabling new populations to arise from a single plant. Seed can germinate readily in different light regimes, over a wide range of temperatures, pH levels and under marginal water stress. Seedlings can emerge from a depth of up to 9 cm. Seedling recruitment can occur within established stands and in soil with a plant litter layer.